Project Description: Water availability is usually the limiting resource for desert ecosystems, and how plants draw sufficient moisture from soils is a complex function of physical and biological conditions. Consideration of ecosystem stability and health must take into account not only plant physiology but also how plants respond to climate and terrain. Although desert vegetation is often comprised of long-lived individuals, these plant types are sensitive to disturbances. Understanding how various ecohydrological factors interact to impact desert vegetation is necessary for monitoring threats under changing climate conditions and other human-caused changes.

In the Mojave Desert, the growth of various plant species is observed to vary with soil and temperature conditions. However, from observations alone, it is difficult disentangle the effects of physical and biological factors on the differences that occur throughout the region. Numerical models that simulate coupled soil-vegetation-climate dynamics can quantify these complex interdependencies, yet results can be sensitive to errors in parameters and other model inputs. In this project, the ecohydrology of the Mojave Desert will be examined using an integrated data and model approach. A physically based ecohydrological model will be developed for a study area in the Mojave Desert. Uncertainty in the model will be reduced by assimilating vegetation and soil moisture data. Data-constrained simulations will provide insight into current control mechanisms on Mojave vegetation growth and help predict how desert habitats may change in the future.